You are in a twisty little maze of Linux distributions and GNU libc
releases, all different.
*/
#define _POSIX_C_SOURCE 200809L
#define _XOPEN_SOURCE 600
+
+ /*
+ * We turn on both _DEFAULT_SOURCE and _BSD_SOURCE to try to get
+ * the BSD u_XXX types, such as u_int and u_short, defined. We
+ * define _DEFAULT_SOURCE first, so that newer versions of GNU libc
+ * don't whine about _BSD_SOURCE being deprecated; we still have
+ * to define _BSD_SOURCE to handle older versions of GNU libc that
+ * don't support _DEFAULT_SOURCE.
+ */
+ #define _DEFAULT_SOURCE
#define _BSD_SOURCE
#endif